S-1

Development and Evaluation of an Air Quality 

Modeling Approach for Lead Emissions from 

Piston-engine Aircraft Operating on Leaded 

Aviation Gasoline 

EDWARD CARR*†, MARK LEE‡, KRISTEN MARIN‡, CHRISTOPHER HOLDER‡, 

MARION HOYER§, MEREDITH PEDDE§, RICH COOK§, AND JAWAD TOUMA!!

†

ICF International, 101 Lucas Valley Road, Suite 260, San Rafael, CA 94903; ‡ICF International; 

§

Environmental Protection Agency Office of Transportation and Air Quality; !!Environmental Protection 

Agency, Office of Research and Development. 

Supporting Information

Prepared for Atmospheric Environment

Pages:

Figures: 18

Tables: 9

 

* Corresponding author phone (415) 507-7186; fax (415) 507-7105; e-mail: ecarr@icfi.com

†

ICF International San Rafael, CA

‡

ICF International Durham, NC 

§ Office of Transportation and Air Quality, National Vehicle Fuels Emission Laboratory

!! Office of Research and Development, Atmospheric Modeling and Analysis Division
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Development and Evaluation of an Air Quality Modeling Approach for Lead

Emissions from Piston-Engine Aircraft Operating on Leaded Aviation Gasoline

Carr, Lee, Marin, Holder, Hoyer, Pedde, Cook, And Touma

S-2

Aircraft Activity Data (Supports 3.1 Aircraft Emissions)

Two sets of aircraft activity data were needed for this analysis: an annual activity dataset and activity data 

for the two periods in which ambient monitoring data were collected). The Airport only maintains records 

of the number of total operations*, jet operations, and helicopter operations. Piston-engine aircraft activity 

was assumed to be the difference between the total operations less the jet and helicopter operations.

Daily records of one year of aviation activity were provided by Santa Monica Airport’s Operations 

Manager, Stelios Makrides. At the time of the analysis, only January 2008 through November 2008 was 

available. When analyzing the three-month seasonal averages for 2008, the winter season consisted of 

only January and February since December 2008 data were unavailable. 

For the 2009 model-to-monitor comparisons, Mr. Makrides provided day-specific counts for the periods: 

March 12th– March 17th, March 26th– March 31st, and July 25th– July 31st, as shown in Table S-1. These 

observed activity data were used in the model-to-monitor comparisons and are typical activity levels, with 

the exception of July 26, 2009 (see explanation in Table S-1). 

Supporting Table S-1. Daily Aircraft Operations at Santa Monica 

Airport

DATE Total Operations Jets Helicopter Propeller

3/12/09 251 34 5 212

3/13/09 352 48 8 296

3/14/09 238 22 2 214

3/15/09 319 34 2 283

3/16/09 337 36 6 295

3/17/09 464 48 2 414

3/26/09 295 34 6 255

3/27/09 453 54 18 381

3/28/09 448 30 8 410

3/29/09 347 42 1 304

3/30/09 349 26 8 315

3/31/09 422 36 8 378

7/25/09 238 32 3 203

7/26/091153 50 7 96

7/27/09 216 38 4 174

7/28/09 409 32 6 371

7/29/09 297 44 10 243

 

*

“Operations” are the number of landings plus takeoffs. 
Supporting Information

Development and Evaluation of an Air Quality Modeling Approach for Lead

Emissions from Piston-Engine Aircraft Operating on Leaded Aviation Gasoline

Carr, Lee, Marin, Holder, Hoyer, Pedde, Cook, And Touma

S-3

Supporting Table S-1. Daily Aircraft Operations at Santa Monica 

Airport

DATE Total Operations Jets Helicopter Propeller

7/30/09 251 30 20 201

7/31/09 329 50 14 265

1 These anomalously low activity data for a Sunday were cross checked with 

the FAA’s ATADS Airport Operations database, which reported a total of 

288 operations for the same day, of which 7 were helicopters. These values 

were used in the monitor-to-model comparison assuming the typical jet 

aircraft fraction determined from other weekend days of 15% or 43 jets, 7 

helicopters, and 238 fixed wing aircraft. 

For the 2008 annual modeling scenario, the average daily activity data are summarized by season and 

weekday/weekend, as shown in Table S-2. Propeller operations (i.e., piston-engine aircraft operations) are 

lowest in winter and there are only slight differences between weekdays and weekends. 

Supporting Table S-2. Average Daily Aircraft Counts at Santa Monica 

Airport for 2008

Season

Total 

Operations

Helicopter 

Operations

Jet 

Operations

Propeller 

Operations

Weekday

Dec- Feb 296.59 7.95 46.59 242.05

Mar-May 364.80 10.41 53.14 301.25

Jun-Aug 373.94 12.72 48.06 313.16

Sep-Nov 368.52 7.57 44.77 316.18

Weekend

Dec- Feb 279.32 5.42 34.89 239.00

Mar-May 355.36 7.46 39.82 308.07

Jun-Aug 330.39 8.68 34.71 287.00

Sep-Nov 287.60 7.00 35.93 244.67

Based on interviews with Airport operational personnel, hourly activity levels were not well known. It 

was determined that this information could best be established by conducting an on-site survey focusing 

on activity levels for piston-engine aircraft. A similar study, but focused on jet aircraft, had been led a few 

years earlier at Santa Monica Airport (SMO) by Professor Keith Mew, Department of Aviation and 

Administration, California State University, Los Angeles. Based on experience from his previous study, 

Dr. Mew led his team of graduate students in conducting a survey of piston-engine aircraft activity during 

two weekend periods in March 2009. A sample survey was performed for six days: March 13, 14 and 15, 

and March 27, 28 and 29 for three periods: morning (8 a.m. and 10 a.m.), midday (10:30 a.m. and 1:30 

p.m.), and afternoon (2 p.m. and 4 p.m.). These periods were selected based on discussions with SMO 
Supporting Information

Development and Evaluation of an Air Quality Modeling Approach for Lead

Emissions from Piston-Engine Aircraft Operating on Leaded Aviation Gasoline

Carr, Lee, Marin, Holder, Hoyer, Pedde, Cook, And Touma

S-4

personnel, who indicated that these times typically covered the most active periods for piston-engine 

aircraft.

The survey collected information on the number of takeoffs and landings as well as the time durations of 

the activities. For departure, data were collected for the following activities: apron to runway end, engine 

run-up, take-off roll, and climb-out. For arrival, data were collected for: approach, landing, and taxi to 

apron (taxi-in). In addition, the following aircraft identification data were collected for each aircraft: tail 

fin number and number of engines (either single or multiple). 

The survey’s data on the temporal distribution based on activity level were the basis for establishing the 

diurnal activity level for aircraft emissions. However, because the survey did not cover all hours of the 

day, the diurnal profile estimated by SMO personnel was used to estimate the distribution for the 

remainder of the hours. Thus, the intraday activity levels were estimated by a combination of survey data 

and professional judgment. 

Figure S-1 shows the piston-engine activity data collected on each survey day, the estimated distribution 

from an interview with SMO staff and the final smoothed distribution used in the analysis (dark black 

line). This figure shows both a late morning peak and a secondary late afternoon peak in activity. This 

temporal profile was used in the modeling for the model-to-monitor comparison for the July 2009 period 

and for the annual modeling. For the March model-to-monitor comparison, the hourly surveyed data were 

used. 

0.00%

5.00%

10.00%

15.00%

20.00%

25.00%

12:00 AM 3:00 AM 6:00 AM 9:00 AM 12:00 PM 3:00 PM 6:00 PM 9:00 PM 12:00 AM Percent of Day Piston-Engine Activity

March 13th March 14th

March 15th March 27th

Marth 28th March 29th

Average of All Days % from SMO personnel interview

Supporting Figure S-1. Hourly activity for piston-engine aircraft at SMO.
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Development and Evaluation of an Air Quality Modeling Approach for Lead

Emissions from Piston-Engine Aircraft Operating on Leaded Aviation Gasoline

Carr, Lee, Marin, Holder, Hoyer, Pedde, Cook, And Touma

S-5

The following sections support 3.2 Other Emission Sources

On-road Sources

Gasoline and diesel fuel contain small quantities of naturally occurring Pb (~ 0.00005 g/L in gasoline1

[EPA 2006]). To accurately include these emissions in the air modeling impact assessment, roadways in 

close proximity to the airport were explicitly modeled. Other on-road mobile source emissions (e.g., 

resuspended road dust) were included as general area source emissions. The Pb emissions from gasoline 

and diesel vehicles for the three major arterials surrounding the airport that were explicitly included in the 

analysis are shown in Figure S-2, and are described as follows:

23rd Street (from Ocean Park Blvd. to Rose St.); 

Ocean Park Blvd. (from 30th St. to South Bundy Dr.); and 

Bundy Dr. (from Ocean Park Blvd. to Airport Ave.).

Daily traffic counts with hourly resolution for Ocean Park Blvd. and 23rd Street were provided by the City 

of Santa Monica. The most recent traffic counts for these two roads were made in 2003. We used U.S. 

census population data2from 2000 to 2007 to project traffic changes for 2008 assuming traffic growth 

increased linearly with population growth. The population in Santa Monica between 2000 and 2007 only 

increased by 3,000 people, or 3.6%. Traffic data for South Bundy came from the 2001-2008 Traffic 

Volume Book, City of Los Angeles3as this roadway is just outside the Santa Monica city limits. The most 

recent traffic counts available for South Bundy Dr. were for National Blvd. at South Bundy and were 

collected on November 18, 2003. As with the other two roadways, the traffic data were linearly scaled 

with Santa Monica population†to estimate traffic volumes in 2008. Table S-3 provides the statistics on 

each road, including length, area, traffic count, and the year the traffic counts were collected. 

The traffic counts did not include estimates on the fleet traffic mix (light duty automobiles, trucks and 

buses). An estimate of these fractions was obtained as follows. Bus data were retrieved from Santa 

Monica’s Big Blue Bus system which provides information on the system maps, bus routes and schedules 

and fleet composition4 The system-wide map of bus routes was reviewed and only buses that travel on 

Ocean Park Blvd., South Bundy Dr., and 23rd St. were analyzed. Only bus routes 6, 8, and 14 travel on 

either Ocean Park Blvd., South Bundy Dr. or both. No buses were found to travel on 23rd St. The bus 

schedules were reviewed to estimate the number of buses per hour that traveled on each road. Santa 

Monica has a large fraction (43%) of buses operating with liquefied petroleum gas (LPG) that do not emit 

Pb. It was assumed that 43% of the buses traveling along Bundy and Ocean Park were fueled with LPG. 

Table S-4 lists the total number of daily bus trips operating on Bundy and Ocean Park per weekday and 

weekend. An additional 5% of the traffic operating on these major arterials was assumed to be diesel 

fueled trucks. 

 

†

Santa Monica population data was used as the change in traffic along this roadway is more affected by Santa 

Monica population changes than the City of Los Angels which encompasses a population spread over an area of 470 

square miles. 
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Development and Evaluation of an Air Quality Modeling Approach for Lead

Emissions from Piston-Engine Aircraft Operating on Leaded Aviation Gasoline

Carr, Lee, Marin, Holder, Hoyer, Pedde, Cook, And Touma

S-6

Source: GoogleEarth.

Supporting Figure S-2. Major roadways in close proximity to SMO explicitly modeled in AERMOD.
Supporting Information

Development and Evaluation of an Air Quality Modeling Approach for Lead

Emissions from Piston-Engine Aircraft Operating on Leaded Aviation Gasoline

Carr, Lee, Marin, Holder, Hoyer, Pedde, Cook, And Touma

S-7

Supporting Table S-3. Traffic Counts for the Three Major 

Roadways near SMO

Street

Length of 

Road (m)

Area of 

Road (m2)

Daily 

Count

Year of 

Count

23rd St. 1,046 11,842 23,958 2003

Ocean Boulevard 853 17,343 31,295 1998

Bundy Dr. 821 16,803 17,700 2003

Supporting Table S-4. Daily Bus Trips on Major Roadways 

near SMO

Street Weekday Saturday Sunday

Bundy Dr. 68 46 32

Ocean Park Blvd. 74 39 39

Emission Calculations

Each roadway source’s emissions were determined as follows: 

Area

Count Veh Len EF HrFrac h r s g mg

Emissions g s m

VehType

08VehType %VehTyp VehTyp 3600 1000

/( 2

Where:

Count08VehType = The 2008 total traffic count for vehicle type, VehType

Veh%VehType = Fraction of vehicle count comprised of vehicle type, VehType. 

Diesel trucks accounted for 5% of vehicles. The percentage of 

vehicles that were diesel buses depended on the street, and was 

calculated by dividing the daily total vehicle count (Table S-3) by 

the daily total bus count (in Table S-4) assuming 57% were diesel 

fueled. The percentage of vehicles that were gasoline fueled 

vehicles was determined by (100% - 5% trucks - X% buses). 

Len = Length of roadway (mile)

EFVehType = Emission factor, in mg Pb per mile of roadway, for vehicle type, 

VehType. The hot stabilized summer emission factor of 0.002 mg 

of Pb/mile was used for gasoline vehicles1,5from dynamometer 

testing of in-use, light-duty vehicles model years 1991-1996). The 

emission factor for diesel fueled truck and bus engines was 

0.00724 mg/mile1,6

HrFrac = The fraction of daily traffic activity per hour of the day, averaged 

across all three roads. These fractions are shown graphically in 
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Development and Evaluation of an Air Quality Modeling Approach for Lead

Emissions from Piston-Engine Aircraft Operating on Leaded Aviation Gasoline

Carr, Lee, Marin, Holder, Hoyer, Pedde, Cook, And Touma

S-8

Figure S-2. An average distribution was used to lessen the bias 

from the single day of sampling. 

Area = The area of each roadway (square meters).

Average Percent of Traffic

0%

2%

4%

6%

8%

10%

12:00 AM

2:00 AM4:00 AM6:00 AM8:00 AM

10:00 AM12:00 PM

2:00 PM4:00 PM6:00 PM8:00 PM

10:00 PM

Time of Day

Percent of Daily Traffic

Supporting Figure S-2. Hourly distribution of traffic on three major roadways 

surrounding SMO.

Area Source Emissions

The area source emission inventory for non-aircraft sources was developed based on the emission 

inventory previously prepared by SCAQMD and the California Air Resources Board (CARB) for the 

Multiple Air Toxics Exposure Study III (MATES-III) (SCAQMD, 2008). These emissions include all 

mobile source emissions not discussed in the preceding sections (e.g., brake and tire wear, re-entrained 

road dust), and all other types of non-road sources (e.g., construction dust, locomotives, fuel combustion, 

cooking). MATES-III started with a 2002 baseline emissions (as used in the 2007 Air Quality 

Management Plan [AQMP]) and was updated to 2005, which was the central year analyzed in MATESIII. Emissions specific to source categories (or Source Classification Codes, SCCs) and to distinct 2x2-km 

grids were developed for the following criteria pollutants and for total organic and total suspended 

particulates pollutant groups speciation were based on the CARB speciation profiles:

Carbon monoxide;

Nitrogen oxides;

Sulfur oxides;

Total organic gases;

Total suspended particulates;

Particulate matter, 10 micrometers and smaller (PM10); and

Particulate matter, 2.5 micrometers and smaller (PM2.5).

The source categories and source classification codes (SCCs) analyzed were part of three larger groups of 

area sources: non-mobile area sources, on-road mobile sources (in two groups: heavy-duty vehicles and 

light- and medium-duty vehicles), and off-road mobile sources. For each of the non-mobile categories, a 

category-specific methodology was used by SCAQMD to derive the criteria pollutant emissions. For on-
Supporting Information

Development and Evaluation of an Air Quality Modeling Approach for Lead

Emissions from Piston-Engine Aircraft Operating on Leaded Aviation Gasoline

Carr, Lee, Marin, Holder, Hoyer, Pedde, Cook, And Touma

S-9

road mobile sources, emission factors from CARB’s EMFAC2007 (v2.3) were coupled with traffic 

activity data from the regional transportation modeling performed by the Southern California Association 

of Governments (SCAG). The coupling of emission factors (g/mile) and traffic activity data (vehicle 

miles traveled) was done using the Caltrans Direct Travel Impact Model (DTIM) to generate hourly 

gridded emissions. For off-road mobile sources, we used CARB’s OFF-ROAD model, which incorporates 

regulations, technology types, seasonal conditions, equipment population, equipment activity, horsepower 

and load factors, and emissions factors to produce annual emissions. The annual emissions were scaled to 

seasonal emissions using spatial and temporal features of the various area grids. This analysis excluded 

from the SCAQMD area source inventory the off-road emissions from aircraft using leaded aviation fuel, 

as these emissions were already developed as described in the previous sections. 

Nine 2x2-km area source grids from the SCAQMD air emission inventory centered approximately on the 

Santa Monica Airport were used to estimate the area source emissions in the vicinity of Santa Monica 

Airport. The SCAQMD 2x2 km emission inventory of annual PM10 emissions was then used for each 

source category or source classification code within each grid in combination with speciation profiles to 

estimate the area source Pb emissions. Speciation profiles were based on several sources as shown in 

Table S-5. The paved road dust and engine exhaust, are to a small degree, a double counting of the onroad emissions as included for 23rd Street, Ocean Blvd and Bundy, however the emissions here are 

distributed over an area of 4 square kilometers and the three additional streets explicitly included 

represent an increase of less than 0.1 in Pb emissions. 

Supporting Table S-5. Pb Emission Factors For Selected Area Sources 

Source Type Weight Percent of PM10 Weight Percent of PM2.5

Unpaved road dust10.013 0.013

Cooking10.0015 0.0014

Construction dust10.07 0.083

Paved road dust 0.0077 0.0077

Gasoline engine exhaust30.016 0.016

Diesel engine exhaust30.016 0.016

Locomotive40.03 0.03

Commercial Ships40.03 0.03

1 General speciation profiles7

2

Site-specific road-side soil samples measured in July 2009 at the northern corner of the airport (Bundy Dr. 

and Ocean Park Boulevard)

3 Health Effects Institute (HEI) Tunnel Study8

4 EPA supplied information

SCAQMD also provided cycle codes to partition the annual emissions to either: (1) each month, day of 

the week, and hour of the day (for non-mobile and off-road sources), or (2) each hour of the day (for onroad emissions). The SCAQMD SCC code for the entrained road dust category for paved roadway 

indicated a flat diurnal profile. This profile was replaced with the diurnal profile for light- and mediumduty vehicles as entrained road dust from paved roadways is expected to be closely related to vehicle 

activity levels. 
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Development and Evaluation of an Air Quality Modeling Approach for Lead

Emissions from Piston-Engine Aircraft Operating on Leaded Aviation Gasoline

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S-10

All area source categories combined accounted for approximately 67 kg/year of Pb across all nine area

source grid cells. The total Pb emissions across all area source types (except piston-fired aircraft) for each 

Level 1 and Level 2 source classification code are presented in Table S-6. Entrained road dust sources 

dominates the collective area source emissions when piston-fired aircraft are excluded, with a total of 41 

kg/year of Pb spread over the 36 square kilometer area. By comparison, the Santa Monica airport pistonfired aircraft emissions (exclusive of climb-out and approach) total about 53 kg/year over an area of just 

one square kilometer. The following three groups of categories together account for another 26% of the 

total area source Pb emissions:

Dust from construction and demolition activities accounts for about 6.6 kg/year of Pb (about 10% 

of the total area source Pb emissions); 

Diesel and gasoline PM from exhaust emissions from on-road vehicles account for about 5.7 

kg/year of Pb (about 9% of the total area source Pb emissions); and 

Cooking activities account for about 5.2 kg/year of Pb (about 7% of the total area source Pb 

emissions). 

Supporting Table S-6. Total Area Source Pb Emissions, Across All Nine Area Source Grids

Source Classification Code 

Level 1 Description

Source Classification Code

Level 2 Description

Total Pb 

Emissions 

(kg/year)

Paved Road Travel Entrained Road Dust 38.5

Cooking Commercial Charbroiling 4.22

Construction And 

Demolition Building Construction Dust- Commercial 3.40

Paved Road Travel Diesel PM [tailpipe exhaust emissions] 3.18

Unpaved Road Travel Entrained Road Dust 2.70

Paved Road Travel Gasoline PM [tailpipe exhaust emissions] 2.49

Construction And 

Demolition Construction And Mining Equipment 1.93

Construction And 

Demolition Building Construction Dust - Institutional 1.79

Paved Road Travel All Brake Wear 1.39

Construction And 

Demolition Building Construction Dust - Residential 1.39

Cooking Cooking (Unspecified) 1.02

Paved Road Travel All Tire Wear 9.84E-01

Construction And 

Demolition Building Construction Dust- Industrial 5.40E-01

Service And Commercial Other 3.02E-01

Service And Commercial Transport Refrigeration Units 2.91E-01
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Development and Evaluation of an Air Quality Modeling Approach for Lead

Emissions from Piston-Engine Aircraft Operating on Leaded Aviation Gasoline

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Supporting Table S-6. Total Area Source Pb Emissions, Across All Nine Area Source Grids

Source Classification Code 

Level 1 Description

Source Classification Code

Level 2 Description

Total Pb 

Emissions 

(kg/year)

Service And Commercial Road Construction Dust 2.85E-01

Service And Commercial Production 2.77E-01

Mineral Processes Grinding/Crushing 1.91E-01

Mineral Processes Fuel Combustion - Water Heating 1.82E-01

Mineral Processes Fuel Combustion - Space Heating 1.81E-01

Mineral Processes Commercial 9.62E-02

Unplanned Fires Automobile Fires 9.53E-02

Trains Locomotives 7.30E-02

Trains Other 7.08E-02

Trains Lawn And Garden (Commercial) 6.99E-02

Trains Other 6.67E-02

Other (Fuel Combustion) I.C. Reciprocating Engines 5.58E-02

Other (Fuel Combustion) Lawn And Garden (Residential) 5.08E-02

Other (Fuel Combustion) Dust From Unpaved Roads And Associated Areas 4.81E-02

Other (Fuel Combustion) Structural Fires 4.49E-02

Other (Fuel Combustion) Commercial (Residential) 3.73E-02

Residential Fuel Combustion Fuel Combustion - Cooking 3.73E-02

Residential Fuel Combustion Lawn And Garden (Other) 3.52E-02

Residential Fuel Combustion Manufacturing 3.12E-02

Residential Fuel Combustion Space Heating 3.05E-02

Residential Fuel Combustion Water Heating 2.93E-02

Residential Fuel Combustion Surface Blasting 2.82E-02

Fugitive Windblown Dust Dust From Pasture Lands 2.10E-02

Metal Processes Secondary Production 1.21E-02

Manufacturing And 

Industrial I.C. Reciprocating Engines 1.21E-02

Manufacturing And 

Industrial Sand And Gravel Excavation And Processing 8.48E-03

Manufacturing And 

Industrial Metrolink 5.81E-03
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Development and Evaluation of an Air Quality Modeling Approach for Lead

Emissions from Piston-Engine Aircraft Operating on Leaded Aviation Gasoline

Carr, Lee, Marin, Holder, Hoyer, Pedde, Cook, And Touma

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Supporting Table S-6. Total Area Source Pb Emissions, Across All Nine Area Source Grids

Source Classification Code 

Level 1 Description

Source Classification Code

Level 2 Description

Total Pb 

Emissions 

(kg/year)

Manufacturing And 

Industrial Other 5.72E-03

Manufacturing And 

Industrial Other 4.72E-03

Manufacturing And 

Industrial Commercial (Other) 4.01E-03

Off-Road Equipment Airport Ground Support Equipment 3.13E-03

Fuel Combustion Other 1.83E-03

Fuel Combustion Trains 1.26E-03

Fuel Combustion Military Tactical Support Equipment 1.04E-03

Fuel Combustion Other 2.53E-04

Fuel Combustion Resource Recovery 3.93E-05

Fuel Combustion Entertainment 2.81E-05

Point Source Emissions

Point sources of Pb include‡sources such as Pb battery recyclers and battery manufacturers, Pb smelters, 

waste incineration, metal industries and glass manufacturers. The SCAQMD maintains an emission 

inventory based on a permit inventory for point source facilities throughout the district. SCAQMD 

provided the location, source code, operation frequencies, and Pb emissions information for 566 point 

source facilities within the South Coast Air Basin. These point source locations and emissions are 

representative of the year 2006, and it was assumed that these data were also representative of 2008. Pb 

emissions for each facility were provided by SCAQMD at the source category code (SCC) level. Some 

facilities reported multiple SCCs associated with Pb emissions. 

Initially, we proposed modeling all point sources within a 20 km radius of SMO. The 86 Pb-emitting 

point source facilities within 20 km of the airport emitted a total of 27.5 kg/year of Pb. However, a 

number of facilities emitting relatively large amounts of Pb were located just outside this radius. These 

additional facilities emitted a total 1,877.8 kg/year of Pb (see Figure S-3) and were dominated by a single 

facility (Exide Technologies – a Pb-acid battery recycling plant as shown on Figure S-3) that emitted 

1,813.5 kg/year Pb. In order to include these substantial Pb 

 

‡ Many other source types are located at fixed locations, but are not significant enough in terms of emissions that 

they are listed as point sources. 
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Development and Evaluation of an Air Quality Modeling Approach for Lead

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Supporting Figure S-3. Point source facilities emitting Pb near SMO. (Larger circles and warmer 

colors reflect greater Pb emissions.)

emissions in the model, all 144 Pb-emitting point sources within a 25 km radius of the airport were 

included in the air quality modeling. The Exide Technologies facility and the seven other facilities that 

together make up 99.5% of the point-source Pb emissions within 25 km of the airport are shown in 

Table S-7. 

Data on physical stack parameters (stack height, diameter, exit gas temperature, and exit gas velocity) are 

needed to model each Pb emissions point source. While SCAQMD was not able to provide any physical 

stack parameters as part of their permit inventory, point source facilities can voluntarily report emissions, 

stack, and process information at the pollutant-level to the EPA’s National Emissions Inventory (NEI). 

However, some of the facilities provided by SCAQMD could not be found in the NEI. In these cases, 

emissions data from SCAQMD were used and physical stack parameters were estimated based on 

parameters provided in the NEI for similar facilities and processes. 
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Development and Evaluation of an Air Quality Modeling Approach for Lead

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Supporting Table S-7. Facilities that Comprise 99.5% of Point Source Pb Emissions Within 25 km 

of SMO

Facility Name Facility City

FacilityAverage 

Latitude 

(UTM 11N)

FacilityAverage 

Longitude 

(UTM 11N)

Lead 

Emissions 

(kg/year)

Cumulative 

Percentage 

Lead 

Emissions 

(lbs/year)

Exide Technologies Los Angeles 3763256 389792 1,813.5 95.2%

Owens-Brockway Glass 

Container Inc Vernon 3761510 388230 27.7 96.6%

Liberty Mfg Inc Los Angeles 3764900 386169 19.1 97.6%

Chevron Products Co. El Segundo 3753601 368842 10.4 98.2%

Glendale City, Glendale 

Water & Power Glendale 3780120 382110 10.3 98.7%

Chevron Products Co. El Segundo 3753601 368842 8.1 99.1%

The Strelitz Co Inc Los Angeles 3761559 382680 3.9 99.4%

U S Radiator Corporation Vernon 3762592 389333 2.8 99.5%

The facilities provided by SCAQMD were manually cross-referenced to the facilities contained in the 

2002 EPA National Emissions Inventory (NEI) Version 3. Though the 2005 NEI is the most current NEI 

available, it was in its early stages of development at the time of analysis (early 2009) and evolving 

quickly. The 2002 NEI was selected because it was likely a more quality-assured and stable dataset. In 

order to account for possible geographic coordinate discrepancies between facilities in both the 

SCAQMD and the NEI, all Pb-emitting facilities in the 2002 NEI Version 3 that were within 27 km of the 

airport were manually matched to the facilities provided by SCAQMD that were within 25 km of the 

airport. The facility matching was based on facility coordinates, facility name, and facility address.

Among the 144 SCAQMD Pb-emitting facilities within 25 km of the airport, 22 facilities were matched 

to facilities in the NEI. Some of the 117 SCAQMD facilities not matched to the NEI may actually be in 

the NEI, but the facility data presented in each database were not consistent enough to make a match 

without further information. For each of the 22 Pb-emitting point source facilities provided by SCAQMD 

that were manually matched to the Pb-emitting point source facilities in the NEI, the physical stack 

parameters of all Pb-emitting sources at the facility were averaged together.§ These facility-level averaged 

physical stack parameters were then used in the air quality modeling. 

For facilities not matched to the NEI, each SCC associated with Pb emissions at a facility was crossreferenced to the “Stack Parameters SCC” table within the 2002 NEI Version 3 Stack Parameter Default 

database. This stack parameter default database provides averages of the physical stack parameters per 

SCC based on all data in the 2002 NEI Version 3. This SCC match was successful for all but one data 

 

§ The 22 SCAQMD matched facilities were matched to 20 facilities in the NEI: 13 of the NEI facilities had only one 

Pb-emitting stack; 2 had 2 stacks with different stack parameters; 2 had 3 stacks (for one, 2 stacks were the same; 

for the other, all 3 stacks were the same); 1 had 4 stacks (3 were the same); 1 had 9 stacks (all different); and 

1 had 27 stacks (26 were the same). 
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Development and Evaluation of an Air Quality Modeling Approach for Lead

Emissions from Piston-Engine Aircraft Operating on Leaded Aviation Gasoline

Carr, Lee, Marin, Holder, Hoyer, Pedde, Cook, And Touma

S-15

record (a record at the SCAQMD Facility ID 800016). For this one data record that was not assigned 

estimated physical stack parameters based on NEI facility data or on NEI SCC data, the record’s source 

industrial classification (SIC) was cross-referenced to the “Stack Parameters SIC” table within the stack 

parameter default database. Appendix B shows the physical stack parameters assigned to each SCC 

associated with Pb emissions at each of the 144 Pb-emitting point source facilities within 25 km of the 

airport.

In addition to Pb emissions, SCAQMD also provided operating schedules for the Pb-emitting point source 

facilities. The following operating schedule data were provided for each source location:

Number of operating hours per day;

Number of operating days per week; and

Number of operating weeks per year.

All of the facilities were in operation at least 5 days per week and at least 48 weeks per year in 2006, but 

without more detailed information about which weeks a facility was non-operational, it was assumed that 

every facility was in operation for every week of the year. Also, all facilities operating 5 days per week 

were assumed to operate Monday through Friday. Since information was available on the number of 

operating hours per day, hourly emissions were developed for three day-of-week groups: week day 

(Monday through Friday), Saturday, and Sunday. For example, if a facility was reported to operate 6 days 

of the week it was assumed to operate Monday through Saturday (see Appendix B for the hourly and 

daily operation schedules). For hourly operations, the SCAQMD inventory provided the number of hours 

per day that the facility operated. It was assumed that this hourly activity was centered on 1300 Local 

Time (LT), though we performed some rounding in order to obtain emission amounts for whole hours 

rather than half-hours. For example, if a facility operated 13 hours of the day, it was assumed to mean the 

facility operated 0630 LT to 1930 LT. However, in order for emissions data to occupy whole hours, it was 

first rounded up to the closing time of 2000 LT (i.e., operating through the 1900 LT hour). This rounding 

forced the opening time to be 0700 LT (2000 LT - 13 hours). Thus, a facility that operated 13 hours of the 

day would have emission estimates for the hours of 0700 LT through 1900 LT. 

Ninety facilities were reported to operate 24 hours a day, 7 days a week. Of the 54 facilities that did not 

operate every hour of every day of the week, 37 operated only during 5 days of the week and 11 operated 

during 6 days of the week. Independent of the number of operating days per week, 25 facilities operated 

only 8 hours of the day, 7 operated 10 hours, 5 operated 12 hours, 1 each operated 13 and 14 hours, 8 

operated 16 hours, and 3 operated 18 hours. 

The following sections support 3.4 Runway Configuration and Aircraft Wake Turbulence

Fixed-wing Aircraft

Vertical (sigma z) and horizontal (sigma y) dispersion parameters were developed for moving (dynamic) 

sources following a mixing zone residence time approach. Sigma y parameters were developed by 

dividing the source separation distance by a standard deviation of 2.15; this is the standard methodology 

used in AERMOD. For initial sigma z, we used the mixing zone residence as defined in CALINE3 model 

by the following equation: 

0.2

30

2 60 1.8 0.11

U

W SZI
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S-16

Where:

SZI = initial vertical dispersion (m)

W2 = half width of the runway or taxiway (m)

U = average wind speed (m/s) over the modeling period 

This equation accounts for the longer time an air parcel spends in the turbulent mixing zone and hence 

greater initial vertical dispersion. Initial sigma y and initial sigma z were developed for each mode of 

aircraft operation as described below: 

Taxi

Initial sigma z

Width of taxiway = 80 feet (24.4m) or W2 = 12.2 m; then apply equation above to estimate initial 

sigma z using the period average wind speed, U. 

Initial sigma y

The horizontal separation distance between source centers is 50 m, thus the initial sigma-y = 

50/2.15 or 23.8 m. 

Takeoff/Approach/Landing/Climb-out (all treated the same) 

Initial sigma z

Width = 35 feet9(average aircraft wingspan) or W2 = 5.34 m, using the equation above using the 

period average wind speed, U. 

Initial sigma y

The horizontal separation distance between source centers is 50 m, thus the initial sigma-y = 

50/2.15 or 23.8 m. 

For the in-flight segment for fixed-wing aircraft, an additional consideration was made to account 

for the wake turbulence created by the forces that lift the aircraft. High pressure air from the 

lower surface of the wings flows around the wing tips to the lower pressure region above the 

wings. A pair of counter-rotating vortices is shed from the wings where the right and left wing 

vortices rotate. It is within this region of rotating air behind the aircraft where wake turbulence 

occurs. To account for this effect, the effective emission height was adjusted for the angle of 

climb (takeoff) and glide slope angle for landing. This adjustment lowers the effective emission 

height to approximate the maximum downward extent of the aircraft’s trailing wake. For SMO, 

this resulted in an angle of climb out for takeoff of approximately 4.8 degrees, while for landing 

this was 2.8 degrees. 

Run-up

Initial sigma z
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Initial sigma z (total) is a total combination of: 

Height above ground Exhaust buoyancy Wind flow over stationary aircraft

Where:

Height above ground = 1.0 m (typical tailpipe height on piston engine aircraft)

Exhaust buoyancy = 0.65 m**

Wind flow over stationary aircraft = Typically two aircraft undergo run-up testing in staging 

area (total area with safe separation distance 100 feet) 

thus W = 30.48 m or W2 = 15.24 m. Then the initial 

sigma z equation (SZI = (1.8 + 0.11* (W2 / U)) * 

(60/30)0.2) is used to determine contribution from wind 

flow over aircraft. 

Then sum these three terms using the period average wind speed, U, to estimate the initial sigma 

z 

Initial sigma y

Initial sigma-y is a total combination of: 

Wingspan wake Horizontal momentum propeller turbulencewake

Where:

Wingspan wake = typically has two wing spans over run-up area (100 feet) or 

W=30.48 m, thus the initial sigma-y from wingspan wake = 

30.48/2.15 or 14.18 m

Horizontal momentum = 0.6 m††

Propeller turbulence wake = 0.85 m‡‡

Total initial sigma-y during run-up = (14.18+0.60+ 0.85) m = 15.63 m 

Rotorcraft (Helicopters) 

For rotorcraft, initial sigma z during idle was based on the typical piston-engine helicopter source height 

of 2.0 m divided by 2.15, or 0.93 m. Initial sigma y was based on the typical helicopter rotor width of 10 

m divided by 4.13, or 2.33 m. For take-off and climb-out, the flight pathway was based on what was used 

for the fixed-wing aircraft because Santa Monica’s noise mitigation program asks that helicopters operate 

in the same flight path as fixed-wing aircraft.10 For landing, the rotorcraft are asked to approach from the 

north or south, perpendicular to the runway, and then descending in a circular motion through 270 degrees 

onto the taxiway with a descent rate of 3 m/s starting at about 275 m (900 feet). The wake turbulence also 

occurs for rotorcraft as high pressure air on the lower surface of the rotor blades flows around the tips to 

 

** Based on sensitivity test with SCREEN3 with and without exhaust temp of 573K.

†† Based on a sensitivity test with SCREEN3 with and without typical exhaust flow of 100 ft3

per minute

‡‡ Based on a typical 6-foot propeller size or 1.83 m; thus initial sigma-y equals 1.83m/2.15 or 0.85 m
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S-18

the lower pressure region above the blades. Consequently, air is forced in a downward trend below the 

main rotor. This combination of actions results in an angle of descent for rotorcraft of 3.7 degrees.

Winter Program Monitoring Results 

Individual Monitoring Results 

Table S-8 summarizes the ambient Pb air monitoring data collected during the winter monitoring program 

at the Santa Monica Airport. The table shows the location of the monitor, the starting date, starting time 

and duration, day of the week in which the sample was collected, the type of monitor used to collect the 

data, and a description of any problems or invalid measurements in the “Comments” column). 

Supporting Table S-8. Pb Air Concentrations from Winter Monitoring Program at SMO 

Sample 

ID Site

Start 

Date

Start 

Time

Duration 

(hh:mm)

Day of 

Week

Pb 

(ng/m3) Type Comments

09-Q46 E.Tarmac 3/12/2009 12:00 07:45 Thursday 24.6 HiVol

09-T1041 E.Tarmac 3/12/2009 12:06 07:30 Thursday 15.6 MiniVol

09-T1042 E.Tarmac 3/12/2009 12:08 07:19 Thursday 16.6 MiniVol

09-T1043 E.Tarmac 3/12/2009 12:05 Unknown Thursday MiniVol Accidentally 

turned off, not 

used in analysis

09-T1045 E.Tarmac 3/12/2009 12:00 07:30 Thursday 13.8 MiniVol

09-T1060 E.Tarmac 3/12/2009 12:00 07:19 Thursday 11.0 MiniVol

09-Q47 E.Tarmac 3/13/2009 8:04 24:41 Friday 45.6 HiVol

09-T1048 W.Tarmac 3/13/2009 8:23 24:53 Friday 10.7 MiniVol

09-T1052 E.Tarmac 3/13/2009 7:22 24:56 Friday 33.6 MiniVol

09-T1055 Clarkson 3/13/2009 8:46 24:59 Friday 40.1 MiniVol

09-T1058 E.Tarmac 3/13/2009 7:19 15: 41 Friday 48.2 MiniVol 11 p.m. shutoff

09-T1059 E.Tarmac 3/13/2009 7:29 25:08 Friday 25.3 MiniVol

09-Q48 E.Tarmac 3/14/2009 9:00 23:38 Saturday 52.6 HiVol

09-T1044 E.Tarmac 3/14/2009 8:24 23:53 Saturday 35.5 MiniVol

09-T1046 Clarkson 3/14/2009 9:43 23:53 Saturday 28.9 MiniVol

09-T1050 W.Tarmac 3/14/2009 9:23 23:40 Saturday 1.8 MiniVol Accidentally 

turned off, not 

used use in the 

analysis

09-T1051 E.Tarmac 3/14/2009 8:35 14:25 Saturday 53.1 MiniVol 11 p.m. shutoff
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S-19

Supporting Table S-8. Pb Air Concentrations from Winter Monitoring Program at SMO 

Sample 

ID Site

Start 

Date

Start 

Time

Duration 

(hh:mm)

Day of 

Week

Pb 

(ng/m3) Type Comments

09-T1040 E.Tarmac 3/15/2009 9:25 23:52 Sunday 45.9 MiniVol Not used in the 

analysis – location of sample 

measurement 

uncertain 

09-Q49 E.Tarmac 3/15/2009 8:48 23:54 Sunday 76.7 HiVol

09-T1047 W.Tarmac 3/15/2009 9:09 24:03 Sunday 6.3 MiniVol

09-T1049 E.Tarmac 3/15/2009 8:33 14:27 Sunday 98.7 MiniVol 11 p.m. shutoff

09-T1054 Clarkson 3/15/2009 9:43 23:47 Sunday 50.1 MiniVol

09-T1057 Clarkson 3/15/2009 9:32 23:54 Sunday 37.5 MiniVol

09-T1061 W.Tarmac 3/15/2009 8:23 24:07 Sunday <detection 

limit

MiniVol below minimum 

detection limit –

which is 3.2 

ng/m3at 68% 

confidence level

09-Q51 E.Tarmac 3/27/2009 8:00 25:02 Friday 82.8 HiVol

09-T1062 E.Tarmac 3/27/2009 7:32 25:07 Friday 48.6 MiniVol

09-T1063 E.Tarmac 3/27/2009 7:40 15:20 Friday 87.6. MiniVol 11 p.m. shutoff

09-T1064 E.Tarmac 3/27/2009 7:45 25:10 Friday 72.5 MiniVol

09-T1065 W.Tarmac 3/27/2009 8:22 25:08 Friday 8.3 MiniVol

09-T1066 Clarkson 3/27/2009 8:38 25:14 Friday 46.0 MiniVol

09-Q52 E.Tarmac 3/28/2009 9:12 23:39 Saturday 39.3 HiVol

09-T1067 E.Tarmac 3/28/2009 8:45 23:49 Saturday 29.6 MiniVol

09-T1068 E.Tarmac 3/28/2009 8:52 14:08 Saturday 46.0 MiniVol 11 p.m. shutoff

09-T1069 W.Tarmac 3/28/2009 9:28 23:53 Saturday <detection 

limit

MiniVol below minimum 

detection limit, 

which is 3.2 ng/ 

m

3

at 68% 

confidence level

09-T1070 W.Tarmac 3/28/2009 9:35 23:37 Saturday 5.0 MiniVol

09-T1071 Clarkson 3/28/2009 9:55 23:46 Saturday MiniVol torn filter

09-Q53 E.Tarmac 3/29/2009 9:00 24:44 Sunday 70.6 HiVol

09-T1072 E.Tarmac 3/29/2009 8:39 24:32 Sunday 59.3 MiniVol
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S-20

Supporting Table S-8. Pb Air Concentrations from Winter Monitoring Program at SMO 

Sample 

ID Site

Start 

Date

Start 

Time

Duration 

(hh:mm)

Day of 

Week

Pb 

(ng/m3) Type Comments

09-T1073 E.Tarmac 3/29/2009 8:47 14:13 Sunday 87.6 MiniVol 11 p.m. shutoff

09-T1074 W.Tarmac 3/29/2009 9:17 23:18 Sunday <detection 

limit

MiniVol below minimum 

detection limit, 

which here is 3.2 

ng/ m3at 68% 

confidence level

09-T1075 Clarkson 3/29/2009 9:38 23:13 Sunday 27.6 MiniVol

09-T1076 Clarkson 3/29/2009 9:38 23:16 Sunday 36.5 MiniVol

09-Q54 E.Tarmac 3/30/2009 9:51 23:25 Monday 43.8 HiVol

09-T1077 E.Tarmac 3/30/2009 9:18 23:34 Monday 31.7 MiniVol

09-T1078 E.Tarmac 3/30/2009 9:27 13:33 Monday 44.6 MiniVol 11 p.m. shutoff

09-T1079 E.Tarmac 3/30/2009 9:31 23:28 Monday 25.5 MiniVol

09-T1080 E.Tarmac 3/30/2009 9:34 23:28 Monday 25.5 MiniVol

09-T1081 E.Tarmac 3/30/2009 9:37 23:26 Monday 33.8 MiniVol

A total of 43 valid data samples were collected over a total of 8 different days. Most samples were 

measured using the MiniVols and in most cases were well above the detection limit. Only the West 

Tarmac location was frequently below the detection limit. Valid data from this study were used in the 

subsequent model-to-monitor comparison. 

Summer Program Monitoring Results 

Individual Monitoring Results 

Table S-9 summarizes the ambient Pb air monitoring data collected during the summer monitoring 

program at Santa Monica Airport. The table shows the location of the monitor, the starting date, starting 

time and ending time, day of the week in which the sample was first collected, the type of monitor used to 

collect the data, and a description of any problems or invalid measurements (in the “Comments” column). 

A total of 28 valid data samples were collected over a total of 7 days. All samples were measured using 

HiVol samplers and in most cases were well above the detection limit. Only the Maintenance Shed 

location (which is located in the predominant upwind direction) showed concentrations below the 

detection limit. The highest monitored concentration was 79 ng/m3 measured Resident 1 on July 26th. 

Valid data from this study were used in the subsequent model-to-monitor comparison. 
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S-21

Supporting Table S-9. Pb Air Concentrations from Summer Monitoring Program at SMO

Sample 

ID Site Start Date

Start 

Time

Duration 

(hh:mm)

Day of 

Week

Pb

(ng/m3) Comment

09-Q539 East Tarmac 7/25/2009 8:16 24:29 Saturday 38.4

09-Q540 Maint.Shed 7/25/2009 8:30 24:40 Saturday 1.5 Just above detection limit of 

1.4 ng/m3at 68% confidence

09-Q541 Resident 1 7/25/2009 7:55 23:40 Saturday 44.4

09-Q542 Resident 2 7/25/2009 8:02 18:28 Saturday 29.6 Shutoff at 2:30 a.m.

09-Q543 East Tarmac 7/26/2009 8:53 23:07 Sunday 57.7

09-Q544 Maint. Shed 7/26/2009 9:20 23:00 Sunday 3.6

09-Q545 Resident 1 7/26/2009 7:40 15:20 Sunday 79.1 Shutoff at 11 p.m.

09-Q546 Resident 2 7/26/2009 8:27 14:33 Sunday 44.7 Shutoff at 11 p.m.

09-Q547 East Tarmac 7/27/2009 8:06 23:05 Monday 53.1

09-Q548 Maint. Shed 7/27/2009 8:30 23:25 Monday 3.5

09-Q549 Resident 1 7/27/2009 7:22 15:38 Monday 51.9 Shutoff at 11 p.m.

09-Q550 Resident 2 7/27/2009 7:40 15:20 Monday 32.4 Shutoff at 11 p.m.

09-Q551 East Tarmac 7/28/2009 7:20 24:25 Tuesday 62.2

09-Q552 Maint. Shed 7/28/2009 8:05 23:20 Tuesday 3.5

09-Q553 Resident 1 7/28/2009 6:42 16:18 Tuesday 75.7 Shutoff at 11 p.m.

09-Q554 Resident 2 7/28/2009 7:00 Unknown Tuesday 50.4 Unknown sample duration -

power lost 

09-Q555 East Tarmac 7/29/2009 7:52 23:28 Wednesday 55.1

09-Q556 Maint. Shed 7/29/2009 7:30 24:10 Wednesday 6.2

09-Q557 Resident 1 7/29/2009 6:47 23:57 Wednesday 32.0

09-Q558 Resident 2 7/29/2009 7:08 23:53 Wednesday 22.5

09-Q559 East Tarmac 7/30/2009 7:25 23:51 Thursday 33.8

09-Q560 Maint. Shed 7/30/2009 7:46 24:51 Thursday < detection limitbelow detection limit of 1.4 

ng/m3at 68% confidence

09-Q561 Resident 1 7/30/2009 6:50 23:50 Thursday 26.9

09-Q562 Resident 2 7/30/2009 7:06 16:09 Thursday 36.4 Shutoff at 11 p.m.

09-Q563 East Tarmac 7/31/2009 7:24 24:55 Friday 45.3

09-Q564 Maint. Shed 7/31/2009 7:45 24:18 Friday 3.3

09-Q565 Resident 1 7/31/2009 6:46 24:49 Friday 38.9

09-Q566 Resident 2 7/31/2009 7:04 16:04 Friday 41.9 Shutoff at 11 p.m.
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S-22

Winter 2009 Model-to-Monitor Results

Clarkson - March 14 Lead Concentration by Source

0

50

100

150

200

250

300

350

9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 1 2 3 4 5 6 7 8

Time of Day

Lead Concentration (ng/m3)

S Runup

S Taxi S

Area

S Takeoff

S Landing

S Climb

S Approach

M Taxi S

M Takeoff

M Taxi N

M Runup

M Landing

M Climb

M Approach

H Taxi S

H Taxi N

H Landing S

H Landing N

H Climb

Light

Point

Offroad

Heavy

Background

Supporting Figure S-4. Clarkson site – March 14 lead concentration by source.
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S-23

East Tarmac - March 14 Lead Concentrations (ng/m3)

0

50

100

150

200

250

9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 1 2 3 4 5 6 7 8

Time of Day

Lead Concentration (ng/m3)

S Runup

Area

S Taxi S

S Takeoff

S Landing

S Climb

S Approach

Point

OfRoad

M Taxi S

M Taxi N

M Takeoff

M Runup

M Landing

M Climb

M Approach

Light

H Taxi S

H Taxi N

H Landing S

H Landing N

H Climb

Heavy

Background

Supporting Figure S-5. East Tarmac site – March 14 lead concentrations (ng/m3).
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S-24

Supporting Figure S-6. Clarkson site – March 28 lead concentrations by source (ng/m3).

Clarkson - March 28 Lead Concentrations by Source (ng/m3)

0

100

200

300

400

500

600

9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 1 2 3 4 5 6 7 8

Time of Day

Lead Concentration (ng/m3)

S Runup

Area

S Taxi S

S Takeoff

S Landing

S Climb

S Approach

Point

Offroad

M Approach

M Taxi S

M Taxi N

M Takeoff

M Runup

M Landing

M Climb

Light

Heavy

H Taxi S

H Taxi N

H Landing S

H Landing N

H Climb

Background
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S-25

East Tarmac - March 28 Lead Concentrations (ng/m3)

0

50

100

150

200

250

300

350

9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 1 2 3 4 5 6 7 8

Time of Day

Lead Concentration (ng/m3)

S Runup

Area

S Taxi S

S Takeoff

S Landing

S Climb

S Approach

Point

OfRoad

M Taxi S

A Approach

M Taxi N

M Runup

M Landing

M Climb

M Approach

Light

H Taxi S

H Taxi N

H Landing S

H Landing N

H Climb

Heavy

Background

Supporting Figure S-7. East Tarmac site – March 28 lead concentrations (ng/m3).
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S-26

Clarkson - March 29 Lead Concentrations by Source (ng/m3)

0

50

100

150

200

250

300

350

400

9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 1 2 3 4 5 6 7 8

Time of Day

Lead Concentration (ng/m3)

S Runup

Area

S Taxi S

S Takeoff

S Landing

S Climb

S Approach

Point

Offroad

M Taxi S

M Taxi N

M Approach

M Takeoff

M Runup

M Landing

M Climb

Light

Heavy

H Taxi S

H Taxi N

H Landing S

H Landing N

H Climb

Background

Supporting Figure S-8. Clarkson site – March 29 lead concentrations by source (ng/m3).
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S-27

East Tarmac - March 29 Lead Concentrations (ng/m3)

0

50

100

150

200

250

300

350

400

450

500

9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 1 2 3 4 5 6 7 8

Time of Day

Lead Concentration (ng/m3)

S Runup

Area

S Taxi S

S Takeoff

S Landing

S Climb

S Approach

Point

OfRoad

M Taxi S

M Approach

M Taxi N

M Runup

M Landing

M Climb

M Approach

Light

H Taxi S

H Taxi N

H Landing S

H Landing N

H Climb

Heavy

Background

Supporting Figure S-9. East Tarmac site – March 29 lead concentrations (ng/m3).
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S-28

Summer 2009 Model-to-Monitor Results

East Tarmac 26th

0

20

40

60

80

100

120

140

160

180

200

9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 1 2 3 4 5 6 7 8

Hour of Day

Lead Concentration (ng/m3)

SRunup

HTaxiN

HTaxiS

MRunup

Light

Heavy

Offroad

Point

Area

HLandS

HLandN

HClimb

MTaxiS

MTaxiN

MTakeoff

MLand

MClimb

MApproach

STaxi

STakeoff

SLand

SClimb

SApproach

Supporting Figure S-10. East tarmac – July 26, 2009 lead concentrations (ng/m3).
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S-29

East Tarmac 27th

0

10

20

30

40

50

60

70

80

90

100

9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 1 2 3 4 5 6 7 8

Hour of Day

Lead Concentration (ng/m3)

SRunup

HTaxiN

HTaxiS

MRunup

Light

Heavy

Offroad

Point

Area

HLandS

HLandN

HClimb

MTaxiS

MTaxiN

MTakeoff

MLand

MClimb

MApproach

STaxi

STakeoff

SLand

SClimb

SApproach

Supporting Figure S-11. East tarmac – July 27, 2009 lead concentrations (ng/m3).
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S-30

East Tarmac 28th

0

50

100

150

200

250

300

9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 1 2 3 4 5 6 7 8

Hour of Day

Lead Concentration (ng/m3)

SRunup

HTaxiN

HTaxiS

MRunup

Light

Heavy

Offroad

Point

Area

HLandS

HLandN

HClimb

MTaxiS

MTaxiN

MTakeoff

MLand

MClimb

MApproach

STaxi

STakeoff

SLand

SClimb

SApproach

Supporting Figure S-12. East tarmac – July 29, 2009 concentrations by source (ng/m3).
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S-31

Residence 1 26th

0

50

100

150

200

250

9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 1 2 3 4 5 6 7 8

Hour of Day

Lead Concentration (ng/m

3

)

SRunup

HTaxiN

HTaxiS

MRunup

Light

Heavy

Offroad

Point

Area

HLandS

HLandN

HClimb

MTaxiS

MTaxiN

MTakeoff

MLand

MClimb

MApproach

STaxi

STakeoff

SLand

SClimb

SApproach

Supporting Figure S-13. Resident 1 – July 26, 2009 lead concentrations (ng/m3).
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Emissions from Piston-Engine Aircraft Operating on Leaded Aviation Gasoline

Carr, Lee, Marin, Holder, Hoyer, Pedde, Cook, And Touma

S-32

Residence 1 27th

0

10

20

30

40

50

60

70

80

90

9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 1 2 3 4 5 6 7 8

Hour of Day

Lead Concentration (ng/m)

3

SRunup

HTaxiN

HTaxiS

MRunup

Light

Heavy

Offroad

Point

Area

HLandS

HLandN

HClimb

MTaxiS

MTaxiN

MTakeoff

MLand

MClimb

MApproach

STaxi

STakeoff

SLand

SClimb

SApproach

Supporting Figure S-14. Resident 1 – July 27, 2009 lead concentrations by source (ng/m3).
Supporting Information

Development and Evaluation of an Air Quality Modeling Approach for Lead

Emissions from Piston-Engine Aircraft Operating on Leaded Aviation Gasoline

Carr, Lee, Marin, Holder, Hoyer, Pedde, Cook, And Touma

S-33

Residence 1 28th

0

20

40

60

80

100

120

140

160

180

9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 1 2 3 4 5 6 7 8

Hour of Day

Lead Concentration (ng/m

3

)

SRunup

HTaxiN

HTaxiS

MRunup

Light

Heavy

Offroad

Point

Area

HLandS

HLandN

HClimb

MTaxiS

MTaxiN

MTakeoff

MLand

MClimb

MApproach

STaxi

STakeoff

SLand

SClimb

SApproach

Supporting Figure S-15. Resident 1 – July 28, 2009 lead concentrations (ng/m3).
Supporting Information

Development and Evaluation of an Air Quality Modeling Approach for Lead

Emissions from Piston-Engine Aircraft Operating on Leaded Aviation Gasoline

Carr, Lee, Marin, Holder, Hoyer, Pedde, Cook, And Touma

S-34

Residence 2 26th

0

20

40

60

80

100

120

140

160

9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 1 2 3 4 5 6 7 8

Hour of Day

Lead Concentration (ng/m

3

)

SRunup

HTaxiN

HTaxiS

MRunup

Light

Heavy

Offroad

Point

Area

HLandS

HLandN

HClimb

MTaxiS

MTaxiN

MTakeoff

MLand

MClimb

MApproach

STaxi

STakeoff

SLand

SClimb

SApproach

Supporting Figure S-16. Resident 2 – July 26, 2009 lead concentrations (ng/m3).
Supporting Information

Development and Evaluation of an Air Quality Modeling Approach for Lead

Emissions from Piston-Engine Aircraft Operating on Leaded Aviation Gasoline

Carr, Lee, Marin, Holder, Hoyer, Pedde, Cook, And Touma

S-35

Residence 2 27th

0

10

20

30

40

50

60

70

80

9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 1 2 3 4 5 6 7 8

Hour of Day

Lead Concentration (ng/m

3

)

SRunup

HTaxiN

HTaxiS

MRunup

Light

Heavy

Offroad

Point

Area

HLandS

HLandN

HClimb

MTaxiS

MTaxiN

MTakeoff

MLand

MClimb

MApproach

STaxi

STakeoff

SLand

SClimb

SApproach

Supporting Figure S-17. Resident 2 – July 27, 2009 lead concentrations (ng/m3).
Supporting Information

Development and Evaluation of an Air Quality Modeling Approach for Lead

Emissions from Piston-Engine Aircraft Operating on Leaded Aviation Gasoline

Carr, Lee, Marin, Holder, Hoyer, Pedde, Cook, And Touma

S-36

Residence 2 28th

0

20

40

60

80

100

120

140

160

180

9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 1 2 3 4 5 6 7 8

Hour of Day

Lead Concentration (ng/m

3

)

SRunup

HTaxiN

HTaxiS

MRunup

Light

Heavy

Offroad

Point

Area

HLandS

HLandN

HClimb

MTaxiS

MTaxiN

MTakeoff

MLand

MClimb

MApproach

STaxi

STakeoff

SLand

SClimb

SApproach

Supporting Figure S-18. Resident 2 – July 28, 2009 lead concentrations (ng/m3).
Supporting Information

Development and Evaluation of an Air Quality Modeling Approach for Lead

Emissions from Piston-Engine Aircraft Operating on Leaded Aviation Gasoline

Carr, Lee, Marin, Holder, Hoyer, Pedde, Cook, And Touma

S-37

Literature Cited

 

1 Air Quality Criteria for Lead - Volume 1; EPA/600/R-05/144aF; National Center for Environmental 

Assessment-RTP Division Office of Research and Development, U.S. Environmental Protection Agency:

Research Triangle Park, NC, October 2006.

2 U.S. Census Bureau Population Trends: Santa Monica City, CA; 

http://factfinder.census.gov/servlet/SAFFPopulation?_event=ChangeGeoContext&geo_id=16000US0670

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3

2001-2008 Traffic Volume Book, Traffic Counts Conducted by City of Los Angeles Department of 

Transportation Traffic Survey Section, http://ladot.lacity.org/tf_hist_auto_counts.htm.

4

Santa Monica Big Blue Bus System, 2009. System map information obtained from

http://www.bigbluebus.com/busroutes/index.asp; information on bus routes and schedules from

http://www.bigbluebus.com/busroutes/; information on fleet composition from 

http://www.bigbluebus.com/aboutus/index.asp. 

5 Cadle, S.H.; Mulawa, P.A.; Hunsanger, E.C.; Nelson, K.; Ragazzi, R.A.; Barrett, R.; Gallagher, G.L.; 

Lawson, D.R.; Knapp, K.T.; Snow, R. Composition of light-duty motor vehicle exhaust 

particulate matter in the Denver, Colorado area. Environ. Sci. Technol.1999, 33: 2328-2339.

6

Lowenthal, D.H.; Zielinska, B.; Chow, J.C.; Watson, J.G.; Gautam, M.; Ferguson, D.H.; Neuroth, G.R.; 

Stevens, K.D. Characterization of heavy-duty diesel vehicle emissions. Atmos. Environ. 1994, 

28: 731-743.

7 California Emission Inventory and Reporting System (CEIDARS), Particulate Matter Speciation Profile.

California Air Resource Board: September 2002. 

8 Characterization of Metals Emitted from Mobile Sources, Research Report Number 133. Health Effects 

Institute: March 2006.

9 Montgomery, M.R., and Foster, G. A Field Guide to Airplanes, 3rd Edition; Houghton Mifflin Company, 

NY, NY, 2006. 

10 City of Santa Monica – Requested Flight Paths (d) Helicopter;

http://www01.smgov.net/airport/n_flights.aspx.